1. Field of Invention
The present invention relates to a manufacturing method of a semiconductor structure.
2. Description of Related Art
When a chip designed to be as an image sensor (e.g., a CMOS chip) is manufactured, a glass sheet is often used to cover the surface of the wafer for protection, such that dust is not apt to attach to the image-sensing region of the wafer. When the chip formed by dicing the wafer is used in an electronic product, a light transmissive sheet is often disposed on a housing of the electronic product aligned with the chip, and the light transmissive sheet has a protection function similar to a glass sheet on the surface of the wafer, thereby wasting material cost and reducing light transmittance.
However, when the glass sheet is not disposed on the surface of the wafer, although the light transmittance may be improved to enhance the image-sensing capability of the chip that is formed by dicing the wafer, the thickness of the wafer is significantly thin and it is very difficult to move such a wafer which has a ball grid array.
Moreover, if there is no other element to protect the image-sensing region during an image sensor manufacturing process, the image-sensing region is apt to be polluted by dust, such that the yield rate of image sensor is difficult to be improved. Although a tape may be used to cover the image-sensing region to protect the image-sensing region during the manufacturing process, the tape without any design is difficult to remove from the wafer after being cut (i.e., the chip), which is an inconvenient factor for manufacturers.